Field of the Invention
The invention relates to a cooling-water pump for a power plant. It furthermore relates to a method for producing a cooling-water pump of this kind.
In a power plant, it is customary practice to provide a cooling-water system containing a number of cooling-water pumps. Owing to the quantities of cooling water to be pumped, these cooling-water pumps are generally embodied as very large-dimension components, it being possible, for example, for an impeller diameter of up to 1.80 m to be provided. Owing to the size of these components, cooling-water pumps are generally only assembled at the location of use. By virtue of the fact that assembly takes place only at the location of use, the housing of the cooling-water pumps can be cast from concrete.
A cooling-water pump of this kind with a cast-concrete pump housing is known, for example, from Published, European Patent Application EP 0 101 628 A1. With this known pump, which is in the form of a spiral concrete pump, the housing includes a preprepared thin-walled formwork wall made of reinforced concrete. As an alternative, the housing of a spiral concrete pump of this kind can, however, also be produced using a wooden formwork that is removed after the concrete housing has been cast.
Cooling-water pumps of this kind are subject to special requirements in regards to a smooth inner surface of the pump housing. In the case of the known cooling-water pumps, these requirements can only be met with a particularly high outlay. Moreover, it is only possible to maintain the required dimensional accuracy for the internal dimensions of the pump housing to a limited extent.
It is accordingly an object of the invention to provide a cooling-water pump and a method for its production which overcome the above-mentioned disadvantages of the prior art devices and methods of this general type, which has a particularly smooth inner surface and the maintenance of particularly high dimensional accuracy of the pump housing is ensured by simple measures.
With the foregoing and other objects in view there is provided, in accordance with the invention, a cooling-water pump for a power plant, containing a pump housing cast from concrete and a number of formwork elements made of a glass-fiber reinforced plastic.
As regards the cooling-water pump, the object is achieved, according to the invention, by a pump housing which is cast from concrete and has a number of formwork elements made of glass-fiber reinforced plastic.
Here, the invention is based on the consideration that a smooth inner surface for the housing and a high dimensional accuracy of the pump housing can be achieved by a special configuration of the formwork used in the production of the pump housing. The material used to produce the formwork, in particular, is very significant in this context. For this purpose, formwork elements made of glass-fiber reinforced plastic are provided.
The cooling-water pump is advantageously configured as a spiral concrete pump. In this context, the glass-fiber reinforced plastic formwork elements are expediently inserted in the region of a spiral housing of a spiral concrete pump.
Any desired glass-fiber reinforced plastic can be provided as the material to form the formwork elements. It advantageously contains glass fibers, quartz sand and a synthetic resin.
As regards the method for the production of the cooling-water pump, the object is achieved if a number of prepared formwork elements made of glass-fiber reinforced plastic are assembled at the set-up location of the cooling-water pump to resulting in a formwork which is a lost formwork when the concrete housing of the cooling-water pump is cast.
The glass-fiber reinforced plastic formwork elements can be molded by using standardized negative molds in their production.
In contrast to a conventional formwork, a lost formwork remains at the production site after the production of the respective concrete component and is firmly connected to the respective concrete component after its production. The glass-fiber reinforced plastic formwork elements used as lost formwork thus become integral parts of the concrete housing after the production of the latter. By virtue of the materials properties of glass-fiber reinforced plastic, the pump housing thus has a particularly smooth surface in the region of the formwork elements.
The advantages obtained with the invention are, in particular, that high dimensional accuracy and a particularly smooth inner surface can be achieved through the use of the lost formwork made of glass-fiber reinforced plastic in the production of the concrete housing of the cooling-water pump. The glass-fiber reinforced plastic formwork elements have a particularly high strength, with the result that there is virtually no deformation due to shrinkage or creep, as in the concrete itself, during the production of the concrete housing. Moreover, the entire inner surface of the pump housing, which is exposed to the cooling water flowing through the cooling-water pump, can be formed by the glass-fiber reinforced plastic formwork elements, with the result that it is particularly insensitive to corrosion or chemical attack or abrasion by the cooling water. Furthermore, the glass-fiber reinforced plastic formwork elements have a particularly low weight, making transportation of prepared formwork elements from the production site to the location of use of the cooling-water pump and also the assembly of the pump housing particularly simple.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a cooling-water pump and a method for its production, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawing.